The photocatalytic disinfection of urban waste waters

In this paper we present the results of the photocatalytic disinfection of urban waste water. Two microbial groups, total coliforms and Streptococcus faecalis, have been used as indexes to test disinfection efficiencies. Different experimental parameters have been checked, such as the effect of TiO2, solar or UV-lamp light and pH. Disinfection of water samples has been achieved employing both UV-lamp and solar light in agreement with data shown by other authors. The higher disinfection rates obtained employing an UV-lamp may be explained by the stronger incident light intensity. Nevertheless no consistent differences have been found between TiO2-photocatalysis and direct solar or UV-lamp light irradiation at natural sample pH (7.8). At pH 5 the presence of TiO2 increases the relative inactivation rate compared with the absence of the catalyst. After the photocatalytic bacterial inactivation, the later bacterial reappearance was checked for total coliforms at natural pH and pH 5, with and without TiO2. Two h after the photocatalytic treatment, CFU increment was almost nill. But 24 and 48 h later an important bacterial CFU increment was observed. This CFU increment is slower after irradiation with TiO2 at pH 5 in non-air-purged samples.     

Element determination in environmental samples using Z-GFAAS with variable magnetic field

Electrothermal atomic absorption spectrometry methods with Zeeman effect background correction (Z-GFAAS) for determination of As, Sb, Se, Ag, Cd, Pb, Cu, Fe, Zn, Cr, and Ni in water and sludge samples were developed. The measurements using Z-GFAAS and variable magnetic field at the three-field dynamic mode permit the sensitivity adaptation for higher analytical concentrations. Calibration ranges were expanded over two orders of magnitude within one measurement run by the applying three-field dynamic mode of this correction system. There are presented calibration data, furnace programs, modifiers, and microwave digestion programs of the obviously monitored elements in the environmental samples. Very low detection limits (3σ criterion) were obtained. Quality assurance was checked by the suitable CRM. The study brings simultaneous determination of the samples with different element concentration range and different sample matrixes, as an important application information for an analyst working in the area of the eco-analytical research.     

The effect of thiacloprid formulation on DNA/chromosome damage and changes in GST activity in bovine peripheral lymphocytes

The potential genotoxic effect of thiacloprid formulation on bovine peripheral lymphocytes was evaluated using the comet assay and the cytogenetic endpoints: chromosome aberrations (CAs), sister chromatid exchanges (SCEs) and micronuclei (MNi). Whole blood cultures were treated with the insecticide at concentrations of 30, 60, 120, 240 and 480 μg mL^?1 for 24, 48 h and/or 2 h of incubation. A statistically significant increase in the frequency of DNA damage, as well as in unstable chromosome aberrations (% breaks) were found after exposure to the insecticide at concentrations ranging from 120 to 480 μg mL^?1 (P < 0.05, P < 0.01, P < 0.001). For the detection of stable structural chromosome aberrations (e.g., translocations) and numerical aberrations by the FISH method, three whole chromosome painting probes for bovine chromosomes 1, 5 and 7 (BTA1, BTA5 and BTA7) were used in our experiments. We observed numerical aberrations, but without any statistical significance. Regarding the sister chromatid exchanges, no significant elevation in the SCE frequencies was found after 24-h exposure to the insecticide. A dose-related response in the SCE induction was obtained in bovine cultures after the prolonged time of exposure (48 h) to thiacloprid formulation at concentrations ranging from 120 to 480 μg mL^?1 in each donor (P < 0.05, P < 0.01), which was associated with a reduction of the PI (P < 0.05, P < 0.01). The insecticide failed to produce MNi; however, a significant reduction of CBPI was observed. Using real-time PCR, a decrease in the expression of bovine glutathione S-transferase M3 (GSTM3) was detected at the lowest dose. The higher concentrations of thiacloprid formulation caused an increase in the mRNA expression.     

Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America

Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.     

Daring females,devoted males,and reversed sexual size dimorphism in the sand-dwelling spider <Emphasis Type="Italic">Allocosa brasiliensis</Emphasis> (Araneae,Lycosidae)

Sexual selection theory predicts that a higher investment in offspring will turn females into the selective sex, while males will compete for accessing and courting them. However, there are exceptions to the rule. When males present a high reproductive investment, sex roles can reverse from typical patterns, turning males into the choosy sex, while females locate males and initiate courtship. In many spiders, males are smaller than females, wandering in search of sedentary females and maximizing the number of copulations. In the present study, we present findings on the sand-dwelling wolf spider, Allocosa brasiliensis, evidencing a reversal in typical courtship roles reported for the first time in spiders. Males were bigger than females. Females located males and initiated courtship. Copulation always occurred in male burrows and took place mainly in long burrows. Males donated their burrows to the females after copulation, closing the entrance before leaving with female cooperation from inside. Males would provide females with a secure place for ovipositing, being exposed to predation and diminishing their future mating possibilities until constructing a new burrow. The cost of vacating the burrow and losing the refuge in an unpredictable habitat, such as sand dunes, would explain the courtship roles reversal in this spider species. Results turn A. brasiliensis as a promising model for discussing the determinants of sex roles and the pressures that drive their evolution and maintenance. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Evaluation of potential genotoxic/cytotoxic effects induced by epoxiconazole and fenpropimorph-based fungicide in bovine lymphocytes in vitro

Potential genotoxic/cytotoxic effects of the epoxiconazole/fenpropimorph-based fungicide were investigated using single cell gel electrophoresis and cytogenetic assays: chromosomal aberrations, sister chromatid exchanges, micronuclei and fluorescence in situ hybridization in cultured bovine lymphocytes. No statistically significant elevations of DNA damage and increases in cytogenetic endpoints were seen. However, evident cytotoxic effect presented as a decrease in mitotic and proliferation indices were recorded after exposure of bovine lymphocytes to the fungicide for 24 and 48 h at concentrations ranging from 3 to 15 µg mL^?1 (P < 0.05, P < 0.01, P < 0.001). Similarly, for 24 h an inhibition in the cytokinesis block proliferation index (CBPI) was obtained after exposure to the fungicide at concentrations ranging from 1.5 to 15 µg mL^?1 (P < 0.01, P < 0.001) in each donor.     

Ultrastructural changes in the rabbit liver induced by carbamate insecticide bendiocarb

Carbamates (CB) are used as insecticides and some of them have been registered as human drugs. The mechanism of CB poisoning involves reversible inhibition of acetylcholine esterase. In the present study, we investigated changes in liver ultrastructure in rabbits (Oryctolagus cuniculus) which were administered bendiocarb for 3, 10, 20, and 30 days. Rabbits in all experimental groups received capsules of bendiocarb (96% Bendiocarb, Bayer, Germany) per os daily at a dose of 5 mg/kg of body weight, and after day 11 received the same dose every 48 h. The observed changes were only moderate, focal, and the effect on the liver was not uniform. On the third day of the experiment, injured hepatocytes had dilated bile capillaries with reduced microvilli. There were no visible alterations in the intercellular contacts. Nuclei of these cells were irregular in shape. Many hepatocytes showed considerable increase in the number of peroxisomes. On day 10 of the experiment, the number of peroxisomes was reduced. Other changes, such as dilated rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum were observed on day 20. The number of lipid droplets in hepatocytes gradually increased. Usually they were present in low numbers, but on day 30 of the experiment their number increased significantly. They coalesced and formed a single lipid droplet which changed the shape of the nuclei. The results presented in this study indicate that both short and long-term administration of bendiocarb affects the liver ultrastructure. At the same time we also observed rapid onset of regeneration of the damaged tissue through activation of hepatocytes and oval cells.     

Simple assessment of the reactive aluminium in sediments

The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted region. A single-step extraction with 0.05 mol L⁻¹ ethylenediaminetetraacetic acid (EDTA) was used, and compared with a standardized SEP as reference. The Al contents extracted into Na₂EDTA were in good agreement with the sequential extraction that yeilds mobile and potentially mobile portion of Al. Extracted EDTA contents make up more than 70% of the first-three-step sum of the five-step extraction procedure. Thus, Na₂EDTA extraction of Al could be applied to assess aluminium mobility changes in sediments and soils.